And as a little clarification on Mom's info, the only on-property dining locations in Osceola County are at the All Star Resorts and Wide World of Sports.
Everywhere else in WDW is in Orange County.
And as a side note, it's funny because the hotel taxes are the exact opposite for the counties. Osceola County is 0.5% *cheaper* than Orange County (which is why it's ever-so-slightly-cheaper to stay in a room at Pop Century in Orange than at the All-Stars in Osceola)